diff --git a/Lib/trace.py b/Lib/trace.py
index b104ff085b4..f167fcfad80 100644
--- a/Lib/trace.py
+++ b/Lib/trace.py
@@ -416,7 +416,6 @@ def find_strings(filename):
 
 def find_executable_linenos(filename):
     """Return dict where keys are line numbers in the line number table."""
-    assert filename.endswith('.py')
     try:
         prog = open(filename, "rU").read()
     except IOError, err: